Bathroom Sink Clog-Preventive Popup Stopper with a Hidden Strainer

ABSTRACT

A bathroom sink popup stopper assembly with an integrated strainer invisible from above the sink while in routine use that catches solids in draining water at its very first stage of downstream to effectively prevent any clogs in the drain passage and beyond. The hidden strainer, sandwiched in between the two parts of the popup stopper body and wrapping around the upper part of the popup stopper body, which is conventionally a one-piece device, that is knocked down into two parts in this invention, an upper body and a lower body that can be repeatedly engaged into and disengaged from each other to secure and release the strainer, is accessible, removable, and re-installable, without the need of any tools, from above the sink before and after cleaning or replacement with a new one if preferred or as needed.

REFERENCES CITED

U.S. Patent Documents 1,817,376 August 1931 Izquierdo 4/292 3,010,118 November 1961 Isherwood 4/203 4,164,048 August 1979 Kampfer et al. 4/292 4,380,834 April 1983 Wentz 4/287 4,539,718 September 1985 Haer 4/292 4,932,082 June 1990 Ridgeway 4/287 4,949,406 August 1990 Canelli 4/288 6,023,795 February 2000 Potter 4/652 6,195,819 B1 March 2001 Wang 4/689 6,385,799 May 2002 Doyen 4/679 7,107,634 September 2006 Baird 4/679 Application 20100000011 A1 January 2010 Angarita, et al. 4/287

PRIORITY NOTICE

The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61264791 filed on Nov. 28, 2009, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

This invention relates to a combined strainer and plug or popup stopper for a bathroom sink or lavatory sink, Class 4/287.

The drainpipe clogging of bathroom sinks or lavatory sinks has long been a house-keeping headache. A typical drainage assembly of such a sink comprises of a drain body in which a popup stopper is installed and controlled by a lift rod sitting behind the faucet through a vertical rod and a horizontal rod. The drain body further leads to a drainpipe. The part after the drain body or drain passage, as sometimes is called, and before the drainpipe is usually a U-shaped or P-shaped combination of bended pipes and connections, commonly called a “P-trap”, for the purpose of retaining some draining water to block the sewage gases and odors from flashing back to the sink opening. The dark side of this water trapping is, as occurred quite often in most households, that human hairs, fabric lint, crumbs, soap scum and other solids tend to be trapped and accumulated there, too. Moreover, the part of the horizontal drainpipe immediately beyond the P-trap is another place susceptible to clogging, maybe even more than the P-trap itself, as result of the weakened flow of the drain water climbing up from the bottom of the P-trap and its turning into a horizontal direction. And given enough time it will gradually slow down the water draining and eventually those rubbish will clog the entire drainage.

The current conventional sink popup stoppers, of American Standard, Delta, Kolher, Moen, to name a few, generally have two types in the methods of installations—(1) the tip of the horizontal control rod goes through the hole or one of the two holes in the leg of the popup stopper (“going-through” type), and as a result the popup stopper cannot be removed unless the horizontal rod is released; and (2) the popup stopper is just sitting on the tip of the horizontal rod (“sitting-on” type) without it going through the hole in the stopper leg, and therefore it enables the popup stopper to be pulled out of the drain body without the need to disengage the horizontal control rod. Most manufacturers, especially the after-market manufacturers like Danco Perfect Match, etc. make “universal” stoppers for dual installations, i.e., good for either “sitting-on” or “going-through” types and for different seat-to-opening heights.

One benefit of this kind of “sitting-on” stoppers is that, by pulling the stopper out of the drain body directly, one can easily clean or remove some of the clogging materials such as hairs and others from the stopper body though it will not prevent the clog in the P-trap and beyond. However, when comes the need to clean the clogs in the P-trap and beyond, it is still necessary to disengage all the connections and bended pipes underneath the sink.

To an average household, it is an expensive spending to call in a plumber's service or is a cumbersome DIY job to disengage and clean the popup stopper and the P-trap underneath the sink, and re-install them afterwards.

Some people turn to a strong caustic chemical treatment, of which the result is far from satisfactory with a single application. And it could primarily clean up the clog in the P-trap part of the drainpipe, but not around the stopper.

There have been quite a few attempts to add a strainer or filter assembly to the drainpipe under the sink, like that of Izquierdo, in U.S. Pat. No. 1,817,376, “Drain Strainer” for example, to be set into between the drain body and the P-trap. There are at least two, disclosed in U.S. Pat. No. 4,164,048 “Combination Sink Trap Access Port Filtration Device” by Kampfer et al., and in U.S. Pat. No. 4,539,718 “Drainpipe Strainer” by Haer, which have a strainer to be integrated at the center bottom in the former and at the front bottom of the P-trap in the latter; and there is one design, by Canelli, in U.S. Pat. No. 4,949,406 “Sink Trap Filter Assembly”, that requires an elongated vertical pipe to house a combined trap and filter assembly under the sink. All these innovative inventions nevertheless need major modifications or alterations to the existing drain body and/or P-trap of a sink and need cleaning and some maintenance jobs underneath the sink as well.

Simple, low-cost strainers or strainer-and-stopper combinations, as Isherwood disclosed in U.S. Pat. No. 3,010,118, for example, have been used in households such as in the kitchens and bathtubs, but they have an apparent drawbacks for use in bathroom sinks, which are that the strainer with its position right at the inside bottom of a sink, and directly exposed to the water in the sink may cause contamination of the water there and its visibility from above the sink inevitably generates a sense of dirtiness to users who, unlike in kitchens, expect pure clean water in the sink. A popup plunger for selectively closing a waste drain pipe, disclosed by Wentz in U.S. Pat. No. 4,380,834, comprising a meshed head that is to be partially exposed to the sink opening while at its popup position, can prevent small valuable articles such as contact lens from falling into the drain with the waste water as intended, but much of the small contaminants may be trapped at the sink opening, too, reducing the quality of fresh water in the sink and causing hygiene problems. Moreover, it does not seem to make as its objective to resolve the clogging in the drain passage and in the P-trap and beyond. Ridgeway's June 1990 U.S. Pat. No. 4,932,082, Strainer Cup for Pop-Up Drain Plug, disclosed an invention of a popup stopper with a strainer cup at the lower end to catch small articles passing through the drain pipe opening. However, the strainer cup has to be forced onto the stopper stem through an aperture means at the bottom of the strainer cup, which is very difficult for users to disassemble, clean and replace. A still greater limitation to the practicability of this invention in real life is that, as result of the way it uses to assemble the strainer cup, it is only suitable for the “sitting-on” type of installations, not good for the “going-through” type, which probably makes up more than half of all popup stoppers' installations.

There are recent inventions with a strainer hidden underneath the plug for high-end products, such as the one disclosed by Wang in U.S. Pat. No. 6,195,819, March 2001, for general use, and the one disclosed by Potter et al. in U.S. Pat. No. 6,023,795, February 2000, for commercial uses like on passenger aircrafts or trains. They can effectively prevent clogging, among other objectives of theirs, however they do not seem to quite fit the average household use, due to their complicated structures and high costs, especially the one in the latter requires an internal flange or shoulder at the lower end of the drain body seat, which a typical household bathroom sink drain assembly does not have, to hold the hidden strainer.

Angarita's US Patent Application, 20100000011 A1, published in January 2010, disclosed an invention that has a filter container at the top part of the sink drain passage by permanently connected to the sink outlet flange or has a removable filter with a broader top outer rim, or a filter-flange, sitting over the sink flange. The invention disclosed in this application can be expected to effectively prevent clogs. However, the permanent connection evidently needs some modification or alteration of the existing sink flange and it is thus hard to clean or replace the filter cup by average household users, if not entirely impossible to replace. In the flange-over-flange type of embodiments of the filter cup, one result may likely be to trap static water and accumulate dirt and grease between the two flanges and around the meeting edges of the two, and thus it may tend to contaminate the water in the sink and even corrode the basin flange, instead of protecting the basin flange as claimed. In another embodiment where each time the stopper is raised, the filter cup is raised and exposed over the sink flange, too, which is not only unnecessary but also may be unsightly to an average user.

A recent innovative P-trap replacement in market called PermaFLOW™ Never-Clog Drain, (Doyen, U.S. Pat. No. 6,385,799, May 2002 and Baird, U.S. Pat. No. 7,107,634, September 2006), is a device that can effectively clear the clogs inside the P-trap by manually rotating a dial outside the enlarged and transparent P-trap to turn an inside wiper to loosen the build-up in the trap and drive it away to continue to flow along the drainpipe. A different and effective way to clear the clogs in the trap, it nevertheless remains to be seen how effective it will be to prevent the clogs beyond the P-trap, i.e., the clogs at the beginning of the horizontal drain pipeline where the P-trap's upward end turns into and the flow of the drain water reaches its flat path. Besides, the PermaFLOW™ requires the entire replacement of the original P-trap and its replacement may be constrained by the clearance underneath the sink due to the enlarged size of this new device.

The challenge is to design a state of the art but simple and affordable device, directly applicable to most existing bathroom sinks, especially household bathroom sinks, without any alteration or modification to them, separated from the clean water in sink and invisible during its day-by-day routine use, to effectively catch the solid contaminants in the drain water before they flow into the drainpipe, requiring minimal maintenance by an average adult user without any plumbing background, and no tools should be needed, and especially, requiring not any underneath-the-sink job.

BRIEF SUMMARY OF THE INVENTION

This invention, a bathroom sink clog-preventive popup stopper assembly with a hidden strainer, is the solution. First of all, this invention enables all the parts of an existing bathroom sink drain system to be kept unchanged except the popup stopper, a relatively independent part, of the drainage assembly. A typical existing popup stopper is usually a single-part device though some may be comprised of a few sub-parts due to different materials used and/or conveniences in production processes, or some functional requirements like adjustable height to fit that of the drain passage of the sink. The clog-preventive popup stopper with a hidden strainer of this invention can even keep unchanged all these features which might be unique to each of the different manufacturers while its core functions work effectively, in addition to keeping all other parts of the existing system untouched.

The clog-preventive popup stopper assembly with a hidden strainer of this invention is comprised of three major parts: (1) an upper body with a sealing disc on top and a bolt-like column at bottom; (2) a lower body with a matching female thread opening on top and a seating bottom with a leg in which one or two holes are to accommodate various types and locations of its connections with the horizontal rod of the control mechanism; and (3) the core of the device, a bowl-shaped or cup-shaped or cone-shaped strainer with mesh openings of proper sizes, with a nut that secures the strainer through the small opening at its bottom on to the bolt-like column of the upper body, or releases it from the upper body. After tightening the nut to secure the strainer on it, the upper body can be screwed into the lower body and an improved popup stopper with integrated strainer is ready for use. Once this improved popup stopper assembly is put into a sink drain body to work, the integrated strainer hidden under the sealing disc and separated from the sink becomes invisible from the view above, and the contaminants it collected there will have no effects on the quality of the water in the sink.

There are several different ways of embodiment from the above-mentioned screw-in and -out method of this three-part clog-preventive popup stopper assembly with a hidden strainer of this invention, such as press-to-engage and press-to-release of the upper body into and from the lower body, though the scope, essence and spirit of this invention remains the same, i.e., the conventional one-piece popup stopper body is cross cut down into an upper body and a lower body, to be able to be engaged and disengaged in certain way as needed, to have a strainer sandwiched in between to be removed and re-installed for cleaning or replacement, without the need of releasing the lock-up or engagement of the leg of the popup stopper body with the horizontal control rod underneath the sink.

The dimensions of this three-part popup stopper are to be made and can be made same as most of those existing conventional popup stoppers of different manufacturers and brands, to meet the required dimensions of their various drain bodies. As a result, it is directly replaceable to most all existing drain systems of bathroom sinks. No other parts are needed, and neither any alteration nor any modification to the existing system will ever be required.

The installation of this three-part stopper is same as its matching type of those existing conventional stoppers. If the tip of the horizontal rod of the control mechanism needs to go through the hole in the leg (i.e., the “going-through” type), or one of the two holes in the leg, depending on the height of the drainage passage, the clog-preventive popup stopper assembly with a hidden strainer has them ready as it can also be made into two versions for a choice—one hole or two holes in the leg; if the tip of the horizontal rod of the control mechanism does not need to go through the hole in the leg but the stopper is just to be sitting on the horizontal rod tip (i.e., the “sitting-on” type), the bottom of the improved stopper of either version can have a flat seat ready for the purpose. In that sense, the clog-preventive popup stopper assembly with a hidden strainer of this invention can be easily made into a “universal” version, to be installed in either one of the “going-through” types at certain height, or in the “sitting-on” type.

Once it is installed and it is at the water-stopping position, the water will be held in the sink as needed. Nothing unusual can be seen from above the sink; only the clean water and the shining surface of the sealing disc, just as if a conventional stopper were in place. To drain the used water, push down the lift rod behind the faucet as usual to pop up the stopper, and the water runs down. However, with this stopper installed and at its popup position, the waste water now runs first through the hidden strainer right beneath the sealing disc, instead of running down to the pipe without any straining. All solids greater than the mesh size will be caught and retained in the strainer.

When it comes to the point of cleaning or replacing the strainer, push down the lift rod to make the stopper at its popup position. There is no need to bend down beneath the sink and toil with the disengagement of the horizontal rod and the many piping connections of the P-trap and the drain pipes, nor to deal with the unpleasant smells and messes inside the piping.

For the “going-through” types of installations, hold the sealing disk and turn counter-clock wise until the upper body with the strainer is disengaged from the lower body and pull it out of the drain passage. (If a screw-on sealing disc is used on the stopper as some manufacturers do, first unscrew the disc from the stopper body, and then unscrew the upper stopper body from its lower body and pull it out of the drain passage.) The lower body of the assembly remains engaged with the horizontal rod in the drain passage. Unscrew the securing nut of the strainer on the upper body to separate the strainer from the upper body and do the cleaning.

Re-installation of the cleaned parts or replacement parts neither requires any beneath-the-sink job. Firstly, put the cleaned or new strainer back to the upper body through its small opening at the bottom and tighten the nut; (screw on the sealing disc if it is so manufactured) and then, secondly, insert the strainer-equipped upper body into the drain passage to engage it with the lower body there by turning the sealing disc clock wise. Thanks to the design of the lower body with expanded dimension or added vanes that makes its diameter up to near the inner diameter of the drain passage, the lower body left in the passage always remains straight and co-axial with the drain passage, and as a result the alignment of the two bodies takes little efforts. No tool is needed in either process.

For the “sitting-on” type of installations, it's even easier. Pull the entire popup stopper assembly with a hidden strainer out of the drain passage when it is at the popup position and separate all the three main parts for cleaning. After cleaning or replacing, and putting together all the three as specified, the entire assembly can be dropped back to the drain passage with a little trial-and-error efforts in alignment.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a bathroom sink clog-preventive popup stopper assembly with a hidden strainer of this invention in a “going-through” type installation, i.e., engaged with the tip of the horizontal rod going through one of the two holes in the leg.

FIG. 2 is the three major parts of a clog-preventive popup stopper assembly with a hidden strainer of this invention.

FIG. 3 is the first step of separation of the clog-preventive popup stopper assembly with a hidden strainer of this invention for cleaning or replacing purposes: the upper body with the hidden strainer on is separated from the lower body, which may or may not be retained in the drain passage, depending on the types of installation.

FIG. 4 is a clog-preventive popup stopper assembly with a hidden strainer of this invention in a “sitting-on” type of installation.

DETAILED DESCRIPTION OF THE INVENTION

In order to better understand the design and the working of this invention and its advantages, the following is a detailed explanation by references to the drawings.

There are mainly two existing conventional bathroom sink popup stopper setups that are widely in use all over the world: “going-through” and “sitting-on” types of installation.

In the “going-through” type of installation, which is also called “non-removable”, the stopper is engaged with the horizontal rod, a part of the control mechanism, with the rod tip going through one of the holes at the bottom of the stopper, in accordance with the needed height of the stopper above the rod in relation to the height of the part of the drain passage from the horizontal rod up to the opening of the sink. The popup stopper cannot be removed unless it is disengaged from the horizontal rod.

The designs in the “sitting-on” type, which is also called “removable”, allow the stopper to just sit on the rod tip without it going through a hole. The popup stopper can be removed without the disengagement of the control mechanism. For this “sitting-on” type of installation, some manufacturers like Mico Designs, for example, used a bolt with a big flat head as the seating bottom sitting on the rod tip and screwed into the bottom of the other part of the stopper body to adjust the total height of the stopper within certain range, and they can be separated, too. However, it seems to be limited to quantitative adjustments of the stopper height only, without any qualitative leap in new features and functions.

Most existing bathroom sink popup stoppers in the market are a single-piece part made of plastic or metal, with a sealing disc and an O ring, having fins or vanes on the stem and one or two holes in the leg stretching from a flat seating bottom, a “universal” one for both types of installation. In some cases, the plastic body goes with a screw-on or fixed metal sealing disc or metalized sealing disc as subpart. In anyways, the upper surface of the sealing disc must be perfectly polished, electroplated and shining to generate a view and sense of absolute cleanliness. The reason behind this also explains the inadequateness of the use of a strainer over the stopper. These existing conventional popup stoppers have no strainer with it and contaminant solids in the drain water may go through all the way down to the drainpipe but any part along its passage that is not perfectly smooth and downward tends to accumulate sediments, more and more, to the point of total blockage. To clean the popup stopper and the clogging in the drain body, in the P-trap and beyond, the P-trap tubing and connections must be disengaged in either type of installation, in addition to the job of disengagement of the lift rod control system in the case of a “going-through” type of installation.

FIG. 1 shows an installed (at its popup position) Bathroom Sink Clog-Preventive Popup Stopper Assembly with a Hidden Strainer of this invention, which has an integrated Strainer (30) situated right below the Sealing Disc (12) and the O-ring (14), and therefore the strainer is working effectively at the very beginning of the flow of the drain water but is separated from the clean water in the sink and is invisible from above.

It is realized by knocking down the popup stopper body, conventionally an inseparable single-piece part, into two sub parts (FIG. 2), the Upper Body (10) and the Lower Body (20), with matching threading (16 and 24) added to each, which are to be engaged or disengaged by screwing into or away from each other; and adding the third, sandwiched upwardly in between and wrapping around the Upper Body (10), a Strainer (30) with Mesh Openings (36) all over its Wall (35) that is bowl- or cup-shaped, most preferred as it has the optimal flow area and is easy to clean.

The knock-down of the conventional popup stopper body into two to integrate a strainer to form a clog-preventive popup stopper assembly with a hidden strainer of this invention is a great qualitative leap in its features and functions, and distinguishes it from prior arts that are relevant.

A preferred embodiment of the popup stopper body knock-down is to make the length of the Upper Body (10) (not including the extruded bolt) great enough, for example, greater than 50% of the total height of a usual stopper body, to accommodate a high enough strainer to maximize its volume and can leave a sufficient distance between the Edge (34) of the strainer and the Sealing Disc (12) when assembled, as shown more clearly in FIG. 3.

The strainer may also be manufactured as cone-shaped or in other shapes as far as it meets the requirements.

FIG. 2 shows that the Strainer (30) has a Large Opening (31) on top, with a Ring-Shaped

Edge (34); the diameters of the contoured Strainer Wall (35) below the Ring Edge (34) are gradually going significantly smaller than that of the Ring Edge (34) to ensure a smooth water drain because, if the strainer wall is too close to the inner wall of the drain passage, the water drain may not be smooth enough. The outside diameter of the Ring Edge (34) should be about 1/16 inch less than the inside diameter of the drain body to avoid leaks of solids through the gap or stuck movements upwards or downwards of the stopper inside the drain body cavity. The Strainer (30) has a small Opening for Assembly (33) at its bottom through which the Male Thread (16) at the bottom of the Upper Body (10) is to go out and to hold the Securing Nut (32). Or, in lieu of the nut, it may be designed for the Strainer to have its own female threading in its Opening for Assembly (33) at the bottom.

The O-ring (14) on the Sealing Disc (12) can be made of silicon or rubber or other similar materials. All the other above-mentioned parts can be made of metals, such as brass, stainless steel, copper or plastics or a combination of some of them. The Strainer (30) is preferably made with Mesh Openings (36) sized between 1/64-⅛ inch to ensure its effectiveness in catching the common household waste solids in the sink water, and total area of all the Mesh Openings (36) should be at least 40% of the total area of the Strainer Wall (35) to allow a smooth waste water drain. The distance between the Edge (34) of the Strainer to the edge of the Sealing Disc (12) should be about ⅜ inch to ½ inch to ensure the strainer invisibility; and the height of the strainer should be more than 1 inch to maximize the volume of the strainer to hold the collected waste solids and the interval of two consecutive cleanings.

Under the circumstances of the “going-through” type installations of conventional popup stoppers, as the stopper's leg is locked by the tip of the horizontal pivot rod of the popup control mechanism, the popup stopper can only be removed by a person bending down underneath the sink, loosening the retaining nut, and then pulling off the rod. FIG. 3 shows that this invention makes it possible to separate the Upper Body (10) with the Strainer (30) attached, from the Lower Body (20), and therefore, it is possible and easy to remove the Upper Body (10) with the Strainer (30) attached, just by popping up the Stopper Assembly of this invention, turning the Sealing Disk (12) counter-clock wise until the Upper Body (10) is disengaged from the Lower Body (20) and then pulling the Upper Body (10) with the Strainer (30) still attached to it out of the drain passage from above the sink without any tool, by an average user without any training or background in plumbing. No need of any job underneath the sink. If the Sealing Disc (12) is an add-on sub-part to the Upper Body, for instance, a metal disc screwed on to a plastic Upper Body, it needs only one more step before disengaging the Upper Body from the Lower Body, that is, to unscrew the Sealing Disc first, and then use fingers to hold the exposed vanes or fins or the stem of the Upper Body and turn counter-clock wise, the Upper Body will be disengaged from the Lower Body.

Now that the Upper Body (10) with the attached Strainer (30) is in hand, by unscrewing the Securing Nut (32), the attached Strainer (30) can be easily taken apart from the Upper Body (10) for cleaning or replacing.

After the cleaning or replacement of new strainer as needed or preferred, the re-assembling and re-installation of the Bathroom Sink Clog-Preventive Popup Stopper Assembly with a Hidden Strainer of this invention is simple, just the reverse of the above procedure.

The top of the Lower Body (20) is expanded with Vanes (22), or in other formats of expansion, of which the outer diameter is also made about 1/16 inch less than the inner diameter of the drain body of the sink to ensure the Lower Body (20) coaxial with the drain passage all the time and it will not be tilted and is always straight upwards while remaining in the drain body after the Upper Body is removed so that the opening of the Female Thread (24) in top of the Lower Body (20) is always positioned in the center to be easily aligned with the Male Thread (16) at the bottom of the Upper Body (10) when it is inserted back into the drain passage to be reinstalled.

For the “sitting-on” type of popup stopper installations (shown in FIG. 4), as the Clog-Preventive Popup Stopper Assembly with a Hidden Strainer of this invention is merely sitting on the horizontal pivot rod, without locking up of the stopper leg with the rod tip, the entire Popup Stopper Assembly can be pulled out off the sink directly by holding its Sealing Disk (12) while it is in the popup position and then the Upper Body (10) can be disengaged from the Lower Body (20) to release the Strainer (30) for cleaning or replacing. To re-install, it needs only a little effort for the alignment to let the leg drop into the surrounding gap of the rod tip so that the flat seat can be sitting on the rod tip, instead of the leg standing on the rod tip.

Although the invention has been described with references to a specific embodiment, and occasionally and partially to some others, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications, alternatives and equivalents that fall within the true spirit, essence and scope of the invention. 

1. A strainer integrated into the popup stopper body of a bathroom sink popup stopper assembly comprising: a) an upper body, b) a lower body, and c) a strainer that is held upwardly in between the upper body and the lower body and wrapping around the upper body and catches solids in the drain water at the first stage of its draining flow and therefore effectively prevents drain passage clogging and drainpipe clogging, that is separated from and not exposed to the water in the sink, and as a result, water will not be contaminated by the strainer and the contents in it, and that is also invisible from above the sink while in its routine use.
 2. A popup stopper assembly according to claim 1, wherein the upper body and the lower body have a matching threading added to each other, which are to be engaged or disengaged by screwing into or away from each other, to further engage or disengage the strainer.
 3. A popup stopper assembly according to claim 1, wherein the top of the lower body has vanes of which the diameter is up to the inner diameter of the sink drain passage to ensure the lower body coaxial with the drain passage all the time and that the lower body will not be tilted and is always straight upwards while remaining in the draining passage after the upper body is removed for cleaning or replacing the strainer so that the female thread opening on the top of the lower body is always in the center to be easily aligned with the male threading at the bottom of the upper body when it is inserted back into the drain passage to be re-installed.
 4. A popup stopper assembly according to claim 1, wherein the strainer has meshes openings sized from 1/64 to ⅛ inch.
 5. A popup stopper assembly according to claim 1, wherein the total mesh opening surface area of the strainer should be more than 40% of strainer surface area to ensure smooth water draining.
 6. A popup stopper assembly according to claim 1, wherein the distance between the top edge of the strainer to the edge of sealing disc is between ⅜ inch ½ inch to ensure the strainer invisibility.
 7. A popup stopper assembly according to claim 1, wherein the outside diameter of the top part of the strainer is 1/32 inch to 3/32 inch smaller than the inside diameter of the drain body wall to ensure minimal leakage of solids through the gap and smooth movement of the stopper.
 8. A popup stopper assembly according to claim 1, wherein the height of the strainer is more than 1 inch to maximize the volume of caught solids and the interval of two consecutive cleanings.
 9. A popup stopper assembly according to claim 1, wherein the shape of the strainer is a bowl or cup or cone shaped.
 10. A popup stopper assembly according to claim 1, wherein the upper body, the lower body and strainer can be made of metals, such as brass and stainless steel or plastics or a combination of some of them. 